Oscar-winning actor and U.N. goodwill ambassador Forest Whitaker urged world lawmakers on Monday to speak out to help former child soldiers in Uganda, South Sudan and Myanmar, gang members in Mexico and the United States, and orphans in Syria and other countries.

He said many young people around the world feel marginalized because nobody listens to them and believe their only recourse is violence and extremism.

Whitaker is the special envoy for peace and reconciliation for the U.N. Educational, Scientific and Cultural Organization and was the keynote speaker at the Fourth World Conference of Parliament Speakers held by the Inter-Parliamentary Union which opened Monday.

He said he found during a decade of work with young men and women that they share "deep and widespread discontentment with the political status quo" and are struggling "to define their identities and discover their purposes."

"You have to help these people find their way so they can stand strong," Whitaker told parliament speakers from more than 120 countries. "You have to demonstrate that everyone matters, and that every person in a democracy has power and efficacy. You have to convince them to hope again."

Otherwise, he warned that extremism, intolerance, violence and racism will grow.

"We can't give up on the current generation and simply try again on the next one," he said. "We have to nurture those young women and men now."

Whitaker won an Oscar for his portrayal of Ugandan dictator Idi Amin in 2006's "The Last King of Scotland."